big cleanup of nbconvert.utils.pandoc module. Remove useless functions, less cached values.

IPython/nbconvert/tests/test_pandoc.py

@@ -1,65 +1,75 b''
 """Test Pandoc module"""
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2013 The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import os
 
 from .base import TestsBase
 from ..utils import pandoc
 
 from IPython.testing import decorators as dec
 
 #-----------------------------------------------------------------------------
 # Constants
 #-----------------------------------------------------------------------------
 
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
 
+
 class TestPandoc(TestsBase):
     """Collection of Pandoc tests"""
 
     def __init__(self, *args, **kwargs):
         super(TestPandoc, self).__init__(*args, **kwargs)
         self.original_env = os.environ.copy()
 
     @dec.onlyif_cmds_exist('pandoc')
     def test_pandoc_available(self):
-        """ Test behaviour of pandoc_available() """
+        """ Test behaviour that pandoc functions raise PandocMissing as documented """
+        pandoc.clean_cache()
+
         os.environ["PATH"] = ""
-        assert not pandoc.pandoc_available()
-        try:
-            pandoc.pandoc_available(failmode="raise")
-        except pandoc.PandocMissing:
-            assert True
+        assert pandoc_function_raised_missing(pandoc.get_pandoc_version) == True
+        assert pandoc_function_raised_missing(pandoc.check_pandoc_version) == True
+        assert pandoc_function_raised_missing(pandoc.pandoc, "", "markdown", "html") == True
 
+        # original_env["PATH"] should contain pandoc
         os.environ["PATH"] = self.original_env["PATH"]
-        assert pandoc.pandoc_available()
-        try:
-            pandoc.pandoc_available(failmode="raise")
-        except pandoc.PandocMissing:
-            assert False
+        assert pandoc_function_raised_missing(pandoc.get_pandoc_version) == False
+        assert pandoc_function_raised_missing(pandoc.check_pandoc_version) == False
+        assert pandoc_function_raised_missing(pandoc.pandoc, "", "markdown", "html") == False
+
         
     @dec.onlyif_cmds_exist('pandoc')        
     def test_minimal_version(self):
-        original_minversion = pandoc.minimal_version
+        original_minversion = pandoc._minimal_version
 
-        pandoc.minimal_version = "120.0"
+        pandoc._minimal_version = "120.0"
         assert not pandoc.check_pandoc_version()
 
-        pandoc.minimal_version = pandoc.get_pandoc_version()
+        pandoc._minimal_version = pandoc.get_pandoc_version()
         assert pandoc.check_pandoc_version()
         
 
         
+
+def pandoc_function_raised_missing(f, *args, **kwargs):
+    try:
+        f(*args, **kwargs)
+    except pandoc.PandocMissing as e:
+        print e
+        return True
+    else:
+        return False

IPython/nbconvert/utils/pandoc.py

@@ -1,192 +1,135 b''
 """Utility for calling pandoc"""
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013 the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 from __future__ import print_function
 
 # Stdlib imports
 import subprocess
 import re
 import warnings
 from io import TextIOWrapper, BytesIO
 
 # IPython imports
 from IPython.utils.py3compat import cast_bytes
 from IPython.utils.version import check_version
-from IPython.utils.process import find_cmd, FindCmdError
+from IPython.utils.process import is_cmd_found, FindCmdError
 
 
 from .exceptions import ConversionException
 
 #-----------------------------------------------------------------------------
 # Classes and functions
 #-----------------------------------------------------------------------------
-minimal_version = "1.12.1"
-
-# command line to make pandoc print it's version. It is also the
-# easiest way to make pandoc return at all.
-__pandoc_version_call = ['pandoc', '-v']
-
+_minimal_version = "1.12.1"
 
 def pandoc(source, fmt, to, extra_args=None, encoding='utf-8'):
     """Convert an input string in format `from` to format `to` via pandoc.
 
     Parameters
     ----------
     source : string
       Input string, assumed to be valid format `from`.
     fmt : string
       The name of the input format (markdown, etc.)
     to : string
       The name of the output format (html, etc.)
 
     Returns
     -------
     out : unicode
       Output as returned by pandoc.
 
     Exceptions
     ----------
     This function will raise PandocMissing if pandoc is not installed.
     Any error messages generated by pandoc are printed to stderr.
 
     """
     cmd = ['pandoc', '-f', fmt, '-t', to]
     if extra_args:
         cmd.extend(extra_args)
 
     # this will raise an exception that will pop us out of here
     check_pandoc_version()
     
     # we can safely continue
     p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
     out, _ = p.communicate(cast_bytes(source, encoding))
     out = TextIOWrapper(BytesIO(out), encoding, 'replace').read()
     return out.rstrip('\n')
 
 
-def pandoc_available(failmode="return", warn=False):
-    """Is pandoc available. Relies on `IPython.utils.process.find_cmd`.
-    
-    Parameters
-    ----------
-     - failmode : string
-        either "return" or "raise". See below.
-     - warn : bool
-        issue a user warning if pandoc is not available.
-
-    Return
-    ------
-    out : (Bool, Exception)
-        On success will return True. On failure and failmode=="return" 
-        will return False-valued PandocMissing instance. If failmode is
-        anything else, the function will not return but raise PandocMissing.
-    """
-    
-    try:
-        find_cmd("pandoc")
-        return True
-    except FindCmdError as e:
-        if warn:
-            warnings.warn(
-                "Pandoc cannot be found (find_cmd('pandoc') failed).\n"+
-                "Please check that pandoc is installed:\n" +
-                "http://johnmacfarlane.net/pandoc/installing.html"
-            )
-
-        exc = PandocMissing("pandoc", e)
-        if failmode == "return":
-            return exc
-        else:
-            raise exc
-
-
 def get_pandoc_version():
     """Gets the Pandoc version if Pandoc is installed.
     
     Return
     ------
     If the minimal version is not met, it will probe Pandoc for its version, cache it and return that value.
     If the minimal version is met, it will return the cached version and stop probing Pandoc 
     (unless `clean_cache()` is called).
 
     Exceptions
     ----------
     PandocMissing will be raised if pandoc is unavailable.
     """
+    global __version
 
-    if __cache['version_ok'] and __cache['version']:
-        return __cache['version']
+    if __version is not None:
+        return __version
     else:
-        pandoc_available(failmode="raise")
-        out = subprocess.check_output(__pandoc_version_call, universal_newlines=True)
+        if not is_cmd_found('pandoc'):
+            raise PandocMissing()
+
+        out = subprocess.check_output( ['pandoc', '-v'], universal_newlines=True)
         pv_re = re.compile(r'(\d{0,3}\.\d{0,3}\.\d{0,3})')
-        __cache['version'] = version = pv_re.search(out).group(0)
-        return version
+        __version = pv_re.search(out).group(0)
+        return __version
 
 
 def check_pandoc_version():
     """Returns True if minimal pandoc version is met.
 
     Exceptions
     ----------
     PandocMissing will be raised if pandoc is unavailable.
     """
-    ok = __cache['version_ok']
-    if not ok:
-        __cache['version_ok'] = ok = check_version( get_pandoc_version(), minimal_version )
+    v = get_pandoc_version()
+    ok = check_version(v , _minimal_version )
         if not ok:
-            warnings.warn( "You are using an old version of pandoc (%s)\n" % __cache['version'] + 
-                           "Recommended version is %s.\nTry updating." % minimal_version + 
+        warnings.warn( "You are using an old version of pandoc (%s)\n" % v + 
+                       "Recommended version is %s.\nTry updating." % _minimal_version + 
                            "http://johnmacfarlane.net/pandoc/installing.html.\nContinuing with doubts...",
                            RuntimeWarning, stacklevel=2)
-    return __cache['version_ok']
+    return ok
 
 #-----------------------------------------------------------------------------
 # Exception handling
 #-----------------------------------------------------------------------------
 class PandocMissing(ConversionException):
     """Exception raised when Pandoc is missing. """
-    def __init__(self, cmd, exc, *args, **kwargs):
-        super(PandocMissing, self).__init__( "The command '%s' returned an error: %s.\n" %(" ".join(cmd), exc) +
+    def __init__(self, *args, **kwargs):
+        super(PandocMissing, self).__init__( "Pandoc wasn't found.\n" +
                                              "Please check that pandoc is installed:\n" +
                                              "http://johnmacfarlane.net/pandoc/installing.html" )
-        self.exc = exc
-
-    def __bool__(self):
-        return False
-
-    __nonzero__ = __bool__
-
 
 #-----------------------------------------------------------------------------
 # Internal state management
 #-----------------------------------------------------------------------------
-def clean_cache(new=False):
-    if new:
-        global __cache
-        cache = {}
-        __cache = cache
-    else:
-        cache = __cache
-        cache.clear()
-    
-    cache['version_ok'] = False
-    cache['version'] = None
-    return cache
-
-# The following holds cache values about the pandoc executable.
-__cache = clean_cache(new=True)
+def clean_cache():
+    global __version
+    __version = None
 
+__version = None